The content of the invention
The invention provides a kind of grounding net of transformer substation performance estimating method injected based on ground line current, to solve at present
Measuring method workload is big, the problem of measurement error is larger.
The invention provides a kind of grounding net of transformer substation performance estimating method injected based on ground line current, methods described bag
Include:
Obtain Substation parameters and the original diverting coefficient k of grounding net of transformer substatione2;
Select an aerial earth wire of the transformer station, and the Injection Current I on the aerial earth wirew, measure connect respectively
Enter the total current I of the circuit outflow of the transformer stationw1The electric current I flowed out with transformer neutral pointN;
According to formula Ig=Iw-Iw1-INCalculating obtains the grounding net of transformer substation earth current Ig;
According to formula ke1=Ig/IwCalculating obtains the grounding net of transformer substation diverting coefficient ke1;
Compare the diverting coefficient ke1With original diverting coefficient ke2, assess the security performance of the grounding net of transformer substation.
Optionally, the acquisition Substation parameters, are specifically included:
The transformer station includes n roots aerial earth wire and m telegram in reply cables, wherein, n >=1, m >=0.
Optionally, the total current I of the circuit of the measurement access transformer stationw1, specifically include:
The electric current I of the n-1 roots aerial earth wire outflow of the measurement access transformer stationw2;
The electric current I of the m telegrams in reply cable outflow of the measurement access transformer stationw3。
Optionally, the comparison diverting coefficient ke1With original diverting coefficient ke2, assess the grounding net of transformer substation
Security performance, is specifically included:
Calculate the diverting coefficient ke1With original diverting coefficient ke2Size variation amount;
If the diverting coefficient ke1With original diverting coefficient ke2Variable quantity be more than 20%, then judge that the transformer station connects
Earth mat there may be failure;
If the diverting coefficient ke1With original diverting coefficient ke2Variable quantity be less than or equal to 20%, then judge the change
Power station grounded screen is functional.
The technical scheme that the present invention is provided can include the following benefits:
The grounding net of transformer substation performance estimating method injected based on ground line current that the present invention is provided, methods described is included:
Substation parameters are obtained, calculating obtains the original diverting coefficient k of grounding net of transformer substatione2, an aerial earth wire of transformer station is selected, and
The Injection Current I on the aerial earth wirew, the total current I that the circuit of measurement access transformer station flows out respectivelyw1It is neutral with transformer
The electric current I of point outflowN, according to formula Ig=Iw-Iw1-INCalculating obtains grounding net of transformer substation earth current Ig, according to formula ke1=
Ig/IwCalculating obtains grounding net of transformer substation diverting coefficient ke1, compare diverting coefficient ke1With original diverting coefficient ke2, assess transformer station
The security performance of grounded screen.The grounded screen performance estimating method proposed by the present invention measured based on CURRENT DISTRIBUTION, without being become
The measurement of power station grounding resistance, substantially reduces measurement workload;And this method can be carried out when transformer station normally runs,
Without having a power failure;The result of also this method measurement is influenceed smaller by season, weather.
It should be appreciated that the general description of the above and detailed description hereinafter are only exemplary and explanatory, not
Can the limitation present invention.
Embodiment
Referring to Fig. 2, the grounding net of transformer substation Performance Evaluation side injected based on ground line current provided for the embodiment of the present application
The flow chart of method.
S100:Obtain Substation parameters and the original diverting coefficient k of grounding net of transformer substatione2。
Specifically, the aerial earth wire of transformer station and the quantity of cable are obtained, transformer station includes n roots aerial earth wire and m wires back
Cable, wherein, n >=1, m >=0.Transformer station generally comprises and the aerial earth wire of more than 2 is connected on a plurality of loop line, every loop line, assessment
Before grounding net of transformer substation performance, the aerial earth wire of access transformer station and the quantity and its grounding net of transformer substation of cable are obtained first
Original diverting coefficient ke2。
S200:Select an aerial earth wire of the transformer station, and the Injection Current I on the aerial earth wirew, survey respectively
The total current I of the circuit outflow of amount access transformer stationw1The electric current I flowed out with transformer neutral pointN。
Specifically, an aerial earth wire on a loop line of transformer station to be assessed is selected, is injected on the aerial earth wire
Electric current Iw, as shown in figure 3, the external impressed current source on a certain aerial earth wire in transformer station, uses current probe C1Measure Injection Current
Aerial earth wire on by the aerial earth wire enter transformer station electric current Iw.Enter the electric current I of transformer station by aerial earth wirewBy
Aerial earth wire, cable, transformer neutral point and grounded screen are shunted, and measure the line of access transformer station respectively using current probe
The electric current I of road (aerial earth wire and cable) outfloww1, use current probe C3The electric current I of measuring transformer neutral point outflowN,
And grounded screen earth current can not direct measurement, can calculate and obtain.
The electric current I of the circuit (aerial earth wire and cable) of measurement access transformer stationw1Specific method referring to Fig. 4.
S201:The electric current I of the n-1 roots aerial earth wire outflow of the measurement access transformer stationw2。
S202:The electric current I of the m telegrams in reply cable outflow of the measurement access transformer stationw3。
Specifically, the aerial earth wire of more than two is generally connected on a loop line, and belongs to pass in parallel between aerial earth wire
System, positioned at the both sides of shaft tower.And transformer station includes n roots aerial earth wire (n >=1), current probe C is used2Measure the built on stilts ground of n-1 roots
The electric current I flowed out on linew2.Further, transformer station is typically provided with m telegrams in reply cable (m >=0), and cable can also play shunting action, if treating
Assess transformer station and do not include cable, be then not required to measure the electric current;If m telegram in reply cables are contained in transformer station, because the shunting of cable is made
With using current probe C4The total current I of the m telegrams in reply cable outflow of measurement access transformer stationw3。
When transformer station is not provided with cable, electric current Iw3Size be zero, now access transformer station circuit (aerial earth wire)
The total current I of outfloww1=Iw2;When transformer station is provided with cable, circuit (the aerial earth wire and cable) outflow of access transformer station
Total current Iw1=Iw2+Iw3.Therefore, the electric current of the circuit outflow of access transformer station should depend on the circumstances.
S300:According to formula Ig=Iw-Iw1-INCalculating obtains the grounding net of transformer substation earth current Ig。
Specifically, the electric current I of transformer station is entered by aerial earth wirewBy aerial earth wire, cable, transformer neutral point and connect
Earth mat is shunted, and the electric current of aerial earth wire, cable and transformer neutral point outflow can obtain electric current by current probe measurement
Size, the electric current that the circuit (aerial earth wire and cable) that can measure access transformer station by current probe respectively flows out is Iw1=Iw2+
Iw3, the electric current of transformer neutral point outflow is IN, and grounded screen earth current immeasurability is obtained, but can be calculated by formula (1)
Obtain:
S400:According to formula ke1=Ig/IwCalculating obtains grounding net of transformer substation diverting coefficient ke1。
Specifically, the grounded screen earth current I obtained according to calculatinggGrounding net of transformer substation diverting coefficient k can be obtainede1, meter
Calculating formula is:
Formula (1) is substituted into formula (2), can be obtained:
S500:Compare the diverting coefficient ke1With original diverting coefficient ke2, assess the security of the grounding net of transformer substation
Energy.
Specifically, the diverting coefficient k of obtained grounding net of transformer substation to be assessed will be calculatede1With original diverting coefficient ke2Enter
Row size compares, and the behavior pattern of grounding net of transformer substation is assessed with this.Wherein, original diverting coefficient k is obtainede2Method and step
With obtaining diverting coefficient ke1Method and step is identical, it is important to newly-built into before use, the same of selection transformer station is returned in transformer station
Line, carries out Injection Current experiment, the original diverting coefficient k so obtained on the same aerial earth wire of loop linee2Transported with transformer station
The diverting coefficient k obtained after row a period of timee1Just there is comparativity, so that the performance of grounding net of transformer substation could be assessed.
As shown in figure 5, assessing comprising the following steps that for grounding net of transformer substation performance according to diverting coefficient:
S501:Calculate the diverting coefficient ke1With original diverting coefficient ke2Size variation amount.
S502:If the diverting coefficient ke1With original diverting coefficient ke2Variable quantity be more than 20%, then judge the power transformation
Grounded screen of standing there may be failure.
S503:If the diverting coefficient ke1With original diverting coefficient ke2Variable quantity be less than or equal to 20%, then judge institute
State grounding net of transformer substation functional.
Specifically, diverting coefficient k is comparede1With original diverting coefficient ke2Size, calculate diverting coefficient ke1With original shunting
Coefficient ke2Size variation amount (ke2-ke1)/ke2If, diverting coefficient ke1With original diverting coefficient ke2Variable quantity (ke2-ke1)/
ke2More than 20%, i.e. diverting coefficient substantially diminishes, then shows that the grounding net of transformer substation there may be failure, it is necessary to carry out further
Detection;If diverting coefficient ke1With original diverting coefficient ke2Variable quantity (ke2-ke1)/ke2Less than or equal to 20%, i.e. shunting is
Number change is little, then shows that the grounding net of transformer substation is functional.
The application illustrates the grounding net of transformer substation performance injected based on ground line current that the application is provided with an instantiation
Appraisal procedure.
Funing station before being taken into use, carries out electric current injection testing, the built on stilts ground in an aerial earth wire of rich military A-wire
Enter the electric current I of transformer station on linewFor 1.1kA, while the electric current I of rich another aerial earth wire outflow of force A-wirew2For 0.2kA,
Access the electric current I of aerial earth wire outflow on the All other routes of transformer stationw3For 0.2kA, the electric current I of transformer neutral point outflowNFor
0.1kA, thus calculates and obtains original diverting coefficient ke2For 54.5%.After substation operation 2 years, the weight on same aerial earth wire
New to carry out electric current injection testing, same computational methods, calculating obtains grounding net of transformer substation diverting coefficient ke1For 12.2%, this point
Flow coefficient ke1Much smaller than original diverting coefficient ke2((ke2-ke1)/ke2> 20%), therefore can determine that the grounding net of transformer substation may
There is failure, it is necessary to further be detected.
The grounding net of transformer substation performance estimating method injected based on ground line current that the application is provided, methods described is included:
Obtain Substation parameters and the original diverting coefficient k of grounding net of transformer substatione2;An aerial earth wire of transformer station is selected, and at this
Injection Current I on the line of vacant lotw, electric current IwAerial earth wire, cable, transformer neutral point and grounded screen through accessing transformer station are entered
Row shunting, transformer station includes n roots aerial earth wire and m telegram in reply cables, wherein, the circuit of n >=1, m >=0, respectively measurement access transformer station
The total current I of outfloww1The electric current I flowed out with transformer neutral pointN, and access the total current I of the circuit outflow of transformer stationw1Including
Access the electric current I of the n-1 roots trolley wire outflow of transformer stationw2With the electric current I of the m telegrams in reply cable outflow of access transformer stationw3, i.e. Iw1
=Iw2+Iw3;According to formula Ig=Iw-Iw1-INCalculating obtains grounding net of transformer substation earth current Ig;According to formula ke1=Ig/IwMeter
Calculation obtains grounding net of transformer substation diverting coefficient ke1;Calculate the diverting coefficient ke1With original diverting coefficient ke2Variable quantity, according to
Diverting coefficient ke1With original diverting coefficient ke2Variable quantity assess the security performance of the grounding net of transformer substation.The application is proposed
Based on ground line current inject grounding net of transformer substation performance estimating method, the measurement without carrying out substation grounding resistance, greatly
Reduce measurement workload greatly.And this method can be carried out when transformer station normally runs, without having a power failure.Also by ground connection
When resistance assesses grounded screen performance, overhead line structures grounding resistance and grounding resistance of transformer substation grounding net change with season, weather simultaneously
Become, measurement result influenceed larger by season, weather, and the measurement result that the appraisal procedure that the application is provided is obtained by season,
The influence of weather is smaller.
Those skilled in the art will readily occur to its of the present invention after the disclosure that specification and practice are invented here is considered
Its embodiment.The application be intended to the present invention any modification, purposes or adaptations, these modifications, purposes or
Person's adaptations follow the general principle of the present invention and including undocumented common knowledge in the art of the invention
Or conventional techniques.Description and embodiments are considered only as exemplary, and true scope and spirit of the invention are by following
Claim is pointed out.
Invention described above embodiment is not intended to limit the scope of the present invention..